dml/calcs/bw_fixed.c

0001 /*
0002  * Copyright 2015 Advanced Micro Devices, Inc.
0003  *
0004  * Permission is hereby granted, free of charge, to any person obtaining a
0005  * copy of this software and associated documentation files (the "Software"),
0006  * to deal in the Software without restriction, including without limitation
0007  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
0008  * and/or sell copies of the Software, and to permit persons to whom the
0009  * Software is furnished to do so, subject to the following conditions:
0010  *
0011  * The above copyright notice and this permission notice shall be included in
0012  * all copies or substantial portions of the Software.
0013  *
0014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
0015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
0017  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
0018  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
0019  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
0020  * OTHER DEALINGS IN THE SOFTWARE.
0021  *
0022  * Authors: AMD
0023  *
0024  */
0025 #include "dm_services.h"
0026 #include "bw_fixed.h"
0027
0028
0029 #define MIN_I64 \
0030     (int64_t)(-(1LL << 63))
0031
0032 #define MAX_I64 \
0033     (int64_t)((1ULL << 63) - 1)
0034
0035 #define FRACTIONAL_PART_MASK \
0036     ((1ULL << BW_FIXED_BITS_PER_FRACTIONAL_PART) - 1)
0037
0038 #define GET_FRACTIONAL_PART(x) \
0039     (FRACTIONAL_PART_MASK & (x))
0040
0041 static uint64_t abs_i64(int64_t arg)
0042 {
0043     if (arg >= 0)
0044         return (uint64_t)(arg);
0045     else
0046         return (uint64_t)(-arg);
0047 }
0048
0049 struct bw_fixed bw_int_to_fixed_nonconst(int64_t value)
0050 {
0051     struct bw_fixed res;
0052     ASSERT(value < BW_FIXED_MAX_I32 && value > BW_FIXED_MIN_I32);
0053     res.value = value << BW_FIXED_BITS_PER_FRACTIONAL_PART;
0054     return res;
0055 }
0056
0057 struct bw_fixed bw_frc_to_fixed(int64_t numerator, int64_t denominator)
0058 {
0059     struct bw_fixed res;
0060     bool arg1_negative = numerator < 0;
0061     bool arg2_negative = denominator < 0;
0062     uint64_t arg1_value;
0063     uint64_t arg2_value;
0064     uint64_t remainder;
0065
0066     /* determine integer part */
0067     uint64_t res_value;
0068
0069     ASSERT(denominator != 0);
0070
0071     arg1_value = abs_i64(numerator);
0072     arg2_value = abs_i64(denominator);
0073     res_value = div64_u64_rem(arg1_value, arg2_value, &remainder);
0074
0075     ASSERT(res_value <= BW_FIXED_MAX_I32);
0076
0077     /* determine fractional part */
0078     {
0079         uint32_t i = BW_FIXED_BITS_PER_FRACTIONAL_PART;
0080
0081         do
0082         {
0083             remainder <<= 1;
0084
0085             res_value <<= 1;
0086
0087             if (remainder >= arg2_value)
0088             {
0089                 res_value |= 1;
0090                 remainder -= arg2_value;
0091             }
0092         } while (--i != 0);
0093     }
0094
0095     /* round up LSB */
0096     {
0097         uint64_t summand = (remainder << 1) >= arg2_value;
0098
0099         ASSERT(res_value <= MAX_I64 - summand);
0100
0101         res_value += summand;
0102     }
0103
0104     res.value = (int64_t)(res_value);
0105
0106     if (arg1_negative ^ arg2_negative)
0107         res.value = -res.value;
0108     return res;
0109 }
0110
0111 struct bw_fixed bw_floor2(
0112     const struct bw_fixed arg,
0113     const struct bw_fixed significance)
0114 {
0115     struct bw_fixed result;
0116     int64_t multiplicand;
0117
0118     multiplicand = div64_s64(arg.value, abs_i64(significance.value));
0119     result.value = abs_i64(significance.value) * multiplicand;
0120     ASSERT(abs_i64(result.value) <= abs_i64(arg.value));
0121     return result;
0122 }
0123
0124 struct bw_fixed bw_ceil2(
0125     const struct bw_fixed arg,
0126     const struct bw_fixed significance)
0127 {
0128     struct bw_fixed result;
0129     int64_t multiplicand;
0130
0131     multiplicand = div64_s64(arg.value, abs_i64(significance.value));
0132     result.value = abs_i64(significance.value) * multiplicand;
0133     if (abs_i64(result.value) < abs_i64(arg.value)) {
0134         if (arg.value < 0)
0135             result.value -= abs_i64(significance.value);
0136         else
0137             result.value += abs_i64(significance.value);
0138     }
0139     return result;
0140 }
0141
0142 struct bw_fixed bw_mul(const struct bw_fixed arg1, const struct bw_fixed arg2)
0143 {
0144     struct bw_fixed res;
0145
0146     bool arg1_negative = arg1.value < 0;
0147     bool arg2_negative = arg2.value < 0;
0148
0149     uint64_t arg1_value = abs_i64(arg1.value);
0150     uint64_t arg2_value = abs_i64(arg2.value);
0151
0152     uint64_t arg1_int = BW_FIXED_GET_INTEGER_PART(arg1_value);
0153     uint64_t arg2_int = BW_FIXED_GET_INTEGER_PART(arg2_value);
0154
0155     uint64_t arg1_fra = GET_FRACTIONAL_PART(arg1_value);
0156     uint64_t arg2_fra = GET_FRACTIONAL_PART(arg2_value);
0157
0158     uint64_t tmp;
0159
0160     res.value = arg1_int * arg2_int;
0161
0162     ASSERT(res.value <= BW_FIXED_MAX_I32);
0163
0164     res.value <<= BW_FIXED_BITS_PER_FRACTIONAL_PART;
0165
0166     tmp = arg1_int * arg2_fra;
0167
0168     ASSERT(tmp <= (uint64_t)(MAX_I64 - res.value));
0169
0170     res.value += tmp;
0171
0172     tmp = arg2_int * arg1_fra;
0173
0174     ASSERT(tmp <= (uint64_t)(MAX_I64 - res.value));
0175
0176     res.value += tmp;
0177
0178     tmp = arg1_fra * arg2_fra;
0179
0180     tmp = (tmp >> BW_FIXED_BITS_PER_FRACTIONAL_PART) +
0181         (tmp >= (uint64_t)(bw_frc_to_fixed(1, 2).value));
0182
0183     ASSERT(tmp <= (uint64_t)(MAX_I64 - res.value));
0184
0185     res.value += tmp;
0186
0187     if (arg1_negative ^ arg2_negative)
0188         res.value = -res.value;
0189     return res;
0190 }
0191